I would wait for an exactly a year since the last one.
That would probably be my preference, as a general policy. But a few things make me disagree:
First, I'm really curious about the results, specifically how they compare to mine. At the time of the last one I was almost brand new to LW.
Second, it was cauched as the 2011 Survey, even though we started it on November 1, which seems like an awkward time to do an annual census.
If it's worth saying, but not worth its own post, even in Discussion, it goes here.